Re: Intellivision's CP1610 CPU
Posted: Sat Sep 14, 2013 11:55 am
You may think it's strange that the CP1610 doesn't have an OR instruction, but remember the 6502 doesn't have a NOT instruction (XOR #$FF notwithstanding).
Also, decles are nothing to worry about. The CP1610 is fully capable of using 16-bit words (and is even more efficient in some operations when it can do so), and in fact the only reason they used 10-bit wide ROMs back in those days was to keep costs down. The 10-bit ROMs in the original games feed logical zero to the upper 6 bits to accommodate the 16-bit bus.
Also, decles are nothing to worry about. The CP1610 is fully capable of using 16-bit words (and is even more efficient in some operations when it can do so), and in fact the only reason they used 10-bit wide ROMs back in those days was to keep costs down. The 10-bit ROMs in the original games feed logical zero to the upper 6 bits to accommodate the 16-bit bus.